We are presented with 3660 and 1001. Let's work out the sum.

Step 1: We'll start by adding the digits 0 & 1 in column 1 and get 1.

Step 2: We'll start by adding the digits 6 & 0 in column 2 and get 6.

Step 3: We'll start by adding the digits 6 & 0 in column 3 and get 6.

Step 4: We'll start by adding the digits 3 & 1 in column 4 and get 4.

So, 3660 + 1001 = 4661.

